One of the central problems of motivation is the mechanism by which organisms produce different responses reflecting different motivational 'states' using a common set of effector systems. Related questions concern the physiological and neural mechanisms by which behavioral outputs are modified by learning or during recovery from injury. We plan to study the neural substrates of motivational and learning processes by examining the control of the raptorial strike of the Mantis Shrimp (Stomatopod). Stomatopods were chosen for study because, while offering the physiological and anatomical advantages of an invertebrate preparation capable of appendage regeneration, the raptorial appendage is used in a variety of behavioral contexts (two forms of predatory strike, agonistic strikes, agonistic displays) and is controlled by both visual and tactile sensory inputs. In addition, raptorial strikes can be engendered and perhaps modified by both instrumental and Pavlovian learning paradigms. Behavioral experiments will analyse the form and stimulus control of raptorial movements produced in different behavioral contexts and conditioning paradigms. Changes in function and the time-course of appendage regeneration will be examined. An electronic/photographic transduction system will provide measures of the form, location, force and duration of individual responses. Anatomical studies will describe the neuromuscular apparatus and central projections of the afferent and efferent innervation. This will provide the background and behavioral paradigms for physiological investigations of the neural control of this visuomotor response system. Thus, in addition to conceptual interest for students of motivation and conditioning, these studies will provide a behavioral preparation amenable for analysis of the physiological mechanisms subserving behavioral plasticity (learning and recovery of function).